Yes, as i mentioned it’s really useful for when you have not developed your sense to prove you’re with the real entity and not some imposter.
From my point of view, protection, or at least some kind of banish work, it’s always important, even more when you’re starting. It helps to keep away any unwanted being or energies.
Lbrp
Banishing chant
Servitor that might help
About circle
Circle ( goetic, universal circle, etc) it’s important to keep a safe place (i might be wrong with this). That can also be helped with the triangle that serves as a place to the spirit to manifest (or them could appear behind you, at your side, you get he idea).
The circle has many options, you could buy one, the BALG official page has one actually. You could draw your own circle permanently or in something that you could store when you’re not using it. Some people use salt, some erasable tool.
I remember once i read a member use a blue light on his/her mind as a circle. I, personally, imagine a white ball that grows until covering the place i want as my space inside the circle.