@Athena Welcome to the community! Let’s get you scanning!
You can use the .21O .21P & .21B files just like a .obs and .nav just put them in the [data] folder of your project and then when PCMaster asks for your base station file point it to the .21O file.
That should allow you to get to the next prompt that will ask for you X,Y,Z corrections (unless you need to return to this location or require the point to be exact for a client, you don’t need to change anything here to get a usable .las) click ok and then the trajectory processor will do its magic and you should end up with a point cloud.
Check this video out!