What type of algae eater is it? A chinese algae eater, or a plec? And if it is a plec, what species? A 36g would be too small for a common plec or gibby, would be fine for a bristlenose or two though. If it's either a common or gibby, or indeed if it is a chinese algae eater, you're best off returning them asap. Course, you could be talking about otos or a small plec, so it'd be great if you could tell us what type they are. If it's an oto, you'll need some more of those as they like to live in groups.
You also need at least another 4 tetras of the same type, but some angels will eat tetras so it might be worth reconsidering that (although my hubby keeps angels with tetras, they're in a 6ft very heavily planted tank - we've not lost a tetra yet).
A word of advice though - if your LFS know nothing about fish (and indeed they dont if they've sold you a common plec for a 36g tank lol), I wouldn't take their advice on fish selection for your tank. Take a look around, if you see something you like - dont buy it there and then, come home, have a look online and see if it's compatable, then decide. LFS will tell you fish are suitable
purely to make a sale, and you could get stuck with a tankbuster or predatory fish that could be really unsuitable for your tank