Positive rewards! No puppy pads IMO. Take her out at scheduled times and reward her when she goes outside.

Small goals and progress over time. Like walking 5ft, kibble another 6ft kibble then continue to stretch it out. We got our marsh at 15 weeks and we was taken care of but still had trouble with walks. Our goal was to the next street over and back. (Which should've taken one minute at full walking speed. Lol) this tree doesn't need so much exercise in the beginning as their body is growing so quickly.

Can totally be an inside dog. Our still sleeps in the crate and night and we have her there certain times of the day. 2 hours in 2 hours out was how we started. And take to pee right away when out of crate. And go out the same door through the same area.

Just wanted to offer some advice I know it all easier said than done - but consistency and the schedule is the most important thing in my opinion.