Opt regular to composition scheme

Dear Experts.,

One of My friend have Medical Shop with GSTIN. He is now under Regular Scheme. He will opt Composition SCheme.

How can we convert from Regular to Composition scheme....

Pls see the Details here

Ope.ITC (FY 17-18) -  28734

Pur (1633592 FY 18-19) ITC  - 104749 = 133483

Sale (1548757 FY 18-19) Lia - 95459 = (133483 - 95459 = 38024 Clo Bal.

Now, How to convert composition...?

How to show Stock...?

How to reverse ITC & which values...?

Please give your replies...