Honestly. if you aren't 100% sure you even want to start dating I would give the date sites a swerve. I dipped on and off them for quite a while, I did meet some lovely guys but also some awful ones.
If you do decide to go for it I would be very careful about saying you only want casual dating as guys will misconstrue that as you just want a shag.
Take everything they say with pinch of salt, who they say they are and who they really are are usually poles apart.
Do not give your number out, stick to messaging on the platform for a while until you feel you sort of know them.
You can tell the creeps, they usually show themselves pretty quickly. I could be having a normal conversation with them one minute, and then the next they try and take you down a really inappropriate path. I made my intentions clear from the start and set my own boundaries - do this and no matter how much you think you like someone, if they cross those boundaries then block them.
You just need to be cautious and keep your wits about you and you also need a very thick skin and not take things too personally. It really is a sweet shop mentality out there, not for the faint hearted at all. I always find when I go back on the date sites I start feeling inadequate, self conscious and generally crap. I'm much happier not being on them and so if I don't meet anyone organically then I will just stay single and I am absolutely ok with that.
Don't bother with POF, it really is awful
The FB dating site is ok, as is tinder. Bumble was never any good for me as there wasnt really anyone who lived remotely local. Hinge was ok but I would start with tinder and take it from there.
Good luck!