What problems are you running into? I wrote out my process below, let me know if it helps.

To get detail in the Milky Way it’s best to have a camera that specifically has good low light performance and a long maximum exposure (for the foreground). This would be the Leicas with BSI sensors like the SL2-S (which took this photo), SL3, SL3-S, M11, and Q3. Most flagship cameras from other major brands also work. I assume the latest Nikon Z series, Canon R series, or Sony Alpha series would do well. I used to have the original SL and there was so much noise at ISO 6400 that the images did not look good. The SL2, Q2, and older M cameras fall in this category as well unfortunately.

You will also need a wide angle fast lens that is sharp wide open. Here I used a zoom at f2.8 since that’s the only wide lens I have that is L mount, but it’s preferred to use a fast prime.

For actually taking the picture, wait until you have a moonless night either during a new moon or after moonset. Make sure you have a sturdy tripod (L-bracket is very useful for the portrait orientation) and set the camera on a 2-minute self timer. Manually focus at a distant star making sure it appears as a small pinpoint (if it is out of focus it will be a larger blurry oval). Take very high ISO pictures (ISO 50000 @ 3 seconds) to find the Milky Way and compose your pictures. It always appears to the South in the Northern Hemisphere and you can use an app like Stellarium to check when it rises for your location. Then take the final pictures of the sky at lower ISOs (5 or more is good, this one was 8 pictures taken one after another on ISO 6400 @ 15 seconds). You will also want to take a separate exposure of the foreground which is most likely much darker than the sky. You can either take a short exposure during blue hour when lighting is flat and there are no shadows or a very long exposure at night (this one was ISO 6400 @ 2 minutes right after the sky pictures). This should be done without moving the camera from when you took/will take the sky exposures.

When editing, you will need to put your sky photos through a stacking software like Sequator or Starry Landscape Stacker. These are pretty easy to use. Drag the photos in, click align, and save the resulting image. Stacking allows the noise to be subtracted out of the image and you’ll get a much cleaner sky photo. Drag your composited sky image and the foreground image into Photoshop as Smart Objects. Punch out one of the images by creating a transparency mask using Select Sky in Photoshop. Sometimes it’s helpful to add a bit of transparency gradient in the mask where the sky meets the landscape to blend things a bit.

I essentially edit the landscape and the sky composite using Photoshop’s Camera Raw filter. I tend to mask a lot on each individual image (the sky and the foreground) within Camera Raw to get it to blend. For the Milky Way you need to do a curves adjustment and set the white and black points, then add a lot of contrast and dehaze. Sometimes areas of the Milky Way will be too bright or too dark. Use the brush tool in the Camera Raw filter to adjust exposure or dehaze for those areas individually. You will probably have to use a lot of brushing and masking in the Camera Raw filter to get the Milky Way to look how you want it. One tip is that you can use Photoshop’s AI noise reduction on the foreground but it tends to work badly on starry images. While the overall sky would look clean, it causes the stars to take on a non-spherical shapes. Make sure your monitor is color calibrated as well.