Hi Will,
Have outlined the methods below.
Selection method:
Menu
Selection
Select by location
Picked source layer and target layer
Are within a distance of the source layer feature (distance 100m, 200m, 300m etc.)
Near tool method:
Toolbar
Near tool
Location
Source layer and target layer
Within x metres (100m, 200m, 300m)
Geodesic distances
Thanks,
Madi