Since you're in Belgium, you'll have to be really careful about just reading ingredients. If you can't find the products we talk about here that we know are CG, you'll have to pay attention to the ingredients in the products available to you.

Get a good silicone free sulfate shampoo and clear out the buildup. Start feeding it moisture from there and that should fix the immediate problem. Then you can learn about product application and properties and how to choose products and fine tune those skills :-) You have really pretty hair, nice beachy waves that definitely have a lot of potential to be bombshell waves once they get properly moisturized. Your hair reminds me a LOT of mine when I first quit straightening it.

As dorm room curly's blog mentiones, wavy hair isn't often as dry as curly hair because the oils from your scalp travel down the hair shaft easier. In the long run you might need to low-poo or clarify on a semi-regular basis but like I mentioned, get the dryness issue taken care of first :-)
fine, thin, normal/(low?) porosity. Mod-CG. Usually I can't co-wash more than 1x a week, & sometimes I have to use T-Gel in rotation due to scalp issues.

Co-wash: VO5 Volumizing
Poo: Giovanni 50:50
RO:TN, Nexxus Youth Renewal, Alba Coconut
PT: gelatin PT, ION EC
Stylers: Giovanni mousse, TIGI Curls Rock amplifier (a-cone), Curls Rock Strong Hold Mousse
Gels: SCC spray gel