Need advise :)

Hi Everyone!

Id really appreciate some advice. Attached below is a picture of me post shower with wet (semi dry), unbrushed hair and a pic of me with dry hair when i dont brush it (wet or dry). My problem is whenever I brush it (even when it’s wet) the waves seem to completely disappear and my hair goes straight and a little frizzy. What do you all recommend I should do to look after the waves? Thank you!