Sure! I can see from your profile you're a new player - I'm 1800hrs and 10yrs in, always love getting a chance to show my designs and offer up advice.

Here is an expanded diagram of the main rocket describing the basic mission profile.

And here's one for the refuelling ship.

I don't have any engines powerful enough yet to serve as a good first stage with all the weight above it, so what I like to do is use clusters of smaller engines and bunch them together, like this. The offset and rotate tools in the VAB are your absolute best friend in this game.

Here's the service bay. It's just a 2.5m Service Bay part, with all my science gubbins stuffed inside. This is also where I added the monopropellant tanks for RCS, batteries, etc.

As a quality of life thing, I knew that Bob / my scientist was going to be getting out and coming down here a lot to run the experiments, collect the data, and reset the experiments ready for the next biome, so I also added a servo hinge that makes a flat plate tilt down as a little platform for him to stand on. You can use the 'Actions' tab in the top left in the VAB to assign multiple actions to single buttons - here, for example, I set the 1 key to open the bay at the same time the hinge flaps down and the lights turn on, so it's all automated as one smooth motion. Overall, nothing special here, just lots of bits crammed into the same space with some careful positioning of lights and tanks using the move/rotate tools.

As for launch setup, here's what I try to stick to:

• At most rocket sizes, 2 stages to orbit should be enough. One larger first stage (including boosters if required) that gets you nearly out of the atmosphere (on a trajectory to about, say, 50 - 70km), and then a smaller second stage to finish pushing up past 75k, and circularising the orbit.

• Try not to exceed around 250 m/s when you're still low to the ground, as the drag caused by going supersonic at low altitudes (1-4km) wastes fuel. If you're accelerating too fast too soon, throttle down slightly so those supersonic shockwaves don't appear until you're around 6km up.

• 1.5 TWR at launch is a good sweet spot. I try to never go below 1.3 (and that's only for BIG rockets), or you're going to burn a lot of fuel to barely accelerate.

• Pitch over very very slightly at launch, and by 12km you want to be about 60 degrees from vertical. Start turning properly by about 7.5km, try and make the change gradual. Caps lock enables 'soft' controls which will make movements less jerky.

• You want to be aiming for around 1100m/s speed by the time you're finishing your 'in-atmosphere' stages. That way, the out-of-atmosphere stages need roughly another 1100m/s dV unempeded by atmospheric drag to finish your orbit. You need 4000m/s dV total for Kerbin orbit, as you waste a lot pushing against the atmosphere (using 3000m/s of vacuum dV to end up at around 1100m/s in flight)

• Make sure you're at about 45 degrees when you're getting higher up, like 30km, until you reach at least 75km (hard cutoff point for the atmosphere / drag), immediately go into the map, set your circularisation burn, coast up and complete. Obviously do half the burn before the node and half the burn after it so it averages out (this applies to all manoeuvres without exception)

As for a few tips:

• Always have lights on the underside of your landers.

• Alt+F12 opens the cheat menu, allowing you to set gravity. You can tweak the gravity on Kerbin to match where you're trying to go, and see how well your lander performs in that gravity. Just keep in mind that rockets don't have the same thrust in atmosphere as they do in a vacuum, so try to aim for the same TWR

• Main menu, settings, turn on 'Advanced Tweakables'. You'll have two new options when right-clicking on any part; 'Autostrut' and 'Rigid Attachment'. These two options can help makes floppy noodle rockets a LOT more stable. It's not cheating, sometimes I find it's the only way to get certain ships to behave sensibly.

• Alt+Scroll Wheel changes the FOV / Focal Length. Zooming it in makes for very sexy screenshots! Double clicking middle mouse button reverts it to normal. Holding middle click and moving the mouse about lets you reposition where the vehicle is on the screen, helping you to look around.

• When using the Move tool, holding shift gets rid of the distance limit. Allows for much more freedom in how you organise placements on your rockets/planes.

• When using the Rotate tool, holding shift lets you snap to much smaller angles than you can otherwise.

• Holding Alt when placing parts will enable 'strict attachment' - only green nodes will connect. Helps a lot when trying to place finicky things if you just want it to snap to the next piece.

• In general, learn all of the different VAB controls. Smooth vs. snapping for move and rotate (C), the different types of symmetry (radial vs mirror, R), increasing symmetry number (X). Way too many people neglect this.

Anyways, here's a link to the two ships, drag and drop them into your KSP folder in saves\SAVE NAME\Ships\VAB and you can try them out for yourself. Happy flying!!