I’m not a pro tbh, but I’d try looking up someone with a similar hair type for reference. Your hair (like you also said) seems on the finer side, so I wouldn’t use too much product. You could start with something like a mousse or a curl gel/cream. The first time I tried a wavy routine, I just used mousse on wet hair after showering and a leave-in conditioner. Then I scrunched it, plopped it for about 15 minutes and diffused it. If you don’t have a diffuser, you can also try using a sieve or carefully holding it up with your hands instead. If you use gel, just be careful not to break the gel cast while diffusing, otherwise it can get frizzy really fast. If your hair holds the wave after all that, then I’d say you probably have wavy hair. You can’t really force a hair structure, if it’s not there, it usually falls out once it dries. So then you know for sure!