Hello, below you will find the pattern for crochet square NUMBER 1.
The tutorial is available on YouTube:

If you would like to watch the introduction before you start crocheting these squares, click below:

If you like to read, not to watch, below you find related posts:

TIP 3: How to create crochet graphs in MS Excel 
Crochet squares - introduction

We work in rows.
Work 1 tch and turn the work at the end of every row.

A - background color
B - number color

Start with ch 20 (19 ch + 1 tch) and then work in 2nd st from the hook.

Row 1-2: A19
Row 3-4: A5, B9, A5
Row 5-12: A8, B3, A8
Row 13: A8, B6, A5
Row 14: A5, B6, A8
Row 15: A8, B5, A6
Row 16: A7, B4, A8
Row 17: A8, B3, A8
Row 18-19: A19

See you in next tutorial! :-)