Let's start with the basic straight tile to get the hang of it!
You will need green and brown worsted weight yarn and a 3.5mm hook. At the end of each row chain 1 and turn.
Begin with 25 Foundation Half Double Crochet in green yarn.
If you need any help with that please refer to this post where I provide a detailed tutorial.
For the next 6 rows make 1 Half Double Crochet in each stitch. You will now have a total of 7 green rows.
Then change to brown yarn and make 1 Half Double Crochet in each stitch. Make a total of 6 rows in brown yarn.
Change back to green yarn and make 1 Half Double Crochet in each stitch. Make a total of 7 rows in green yarn.
You will have a total of 20 rows.
Fasten off and tie in any loose ends!