Instead of asking for donations, why not offer manuals at a small price to explain how the features work

instead of asking for donations, why not offer manuals at a small price to explain how the features work.

because it is very time consuming figure how the different features work.

In the future, try something this simple with Google: {PROGRAM NAME} documentation

What about these guides?

instead of asking for donations, why not offer manuals at a small price to explain how the features work.

Donations are used for more than just supporting the production of manuals. In fact, according to this recent TDF blog post the support provided by donations is varied:

we have been able to fund a large number of projects, from hackfests for developers to LibreOffice booths at exhibitions, along with native language community events, a stronger independent infrastructure, and so on. In addition, our staff is growing, taking care of background activities, and making things happen.

As @Lupp pointed out, documentation is freely available to download. However, you can buy a printed paper version from Lulu.com at a small price, the documentation link will point you to Lulu. Profits from the paper version do go to THE Document Foundation.