Dear hauda,
I am not sure if StaMPS is the right tool for landslide analyses to be honest because it was made to measure surface deformation. It depends on the type of your landslide but if it was a sudden event StaMPS might not be very suitable.
To get to know what StaMPS is capable of I recommend this collection of sources: About the STaMPS category
The single steps are discussed at various points among these links.
It is a great too, no doubts, but it takes some time to get reliable results that also make sense. There is no recipe to follow along to get the one “right” output. InSAR strongly depends on the selection of suitable input data and many subsequent steps of the workflow deal with checking plausibility, adjusting variables and re-processing parts to get to a final result.
I don’t want to discourage you in any way but be aware that people took months to get into it. I’m just saying that because your question sounds a bit like “tell me what to do and I repeat it” and unfortunately, it is not that easy. If you have a background in SAR interferometry and simply need to know the technical steps, you will find lots of answers in the topic i mentioned above.
Please also be aware that cross-posting the same question over multiple topics is violating the forum rules and I deleted the other ones.