For Base Stations, you want to have them on opposite ends of the room, with one being roughly above your monitor. Depending on the model and the field of view of the Base Station (2.0 Base Stations have a higher Field of View), you will need to angle it to cover the area you intend to be playing in.
The best way to setup Base Stations is by drilling holes to fasten them in place. Using adhesive or non-destructive hooks are not recommended as the motors inside of them will loosen the adhesive over time and inevitiably cause damage when they fall.
Do you have SteamVR Base Stations 1.0 or 2.0?