Oh, boy. Get yourself a copy of:
1. Tapatalk
2. A Note app (you may already have it)
3. YouTube (you may already have it)
Tapatalk will make it easier to post. Some of the things you took for granted, like the "video" button, you will have to type in manually, using BBCode instead.
A Note App you can use for making up boilerplate text you can copy and paste into your post. Not strictly necessary.
Learn how to cut and paste:
1. cut: hold down finger on text and wait for cut-and-paste menu to pop up. You can select "all" or just use your finger to change the select part, followed by "copy" to get it into the clipboard.
2. paste: hold down finger where you want to paste and wait for cut-and-paste menu to pop up. Select "paste".
If you can get past that part, the rest is not difficult. You can find tutorials on YouTube.