How to report capital gain with lots of disposal

I try to use online self assessment form to report disposal of shares but it only allow input of around 20 disposals.
Can I attach an excel sheet to report the disposal or must I purchase a computer program to do so?

Hi
You should report the total number of disposals on the tax return and a summary total for the disposal value and the acquisition costs for the year and include a breakdown of the disposal as a supplementary attachment.