The Trial Memorandum of the House of Representatives is available here. It sets out the case against the former President.
Trump's defence Memorandum can be accessed here.
There are a number of Congressional Research Papers about the Impeachment of a President - these include -
Click on the relevant name of the paper - and this will give you access to the CRS Papers.
When the trial is in progress, I'm sure that the major news channels such as CNN and BBC News, and of course C-SPAN will give lots of live coverage. Again, just click on the relevant link to take you there. Or if you want the live feed from the Senate itself press here.
As a former lecturer in Constitutional Law, with a deep and specific interest in what happens in the US Congress (scroll through previous posts on Washminster - I can't guarantee that the law and practice remain the same (the blog covered 2007 to 2017 - and much has happened since)) - I'm sure that the next couple of weeks will be filled with reading and watching.
There's a new impetus for me to keep abreast of the news - I start broadcasting on a new internet radio station which launches a fortnight on Friday. It's called Elite Live Radio. My programme is to be called PPS (I'll explain why on air - and later write a post for Washminster) - and is due to air for the first time on Monday February 22nd at Noon, GMT. I hope you'll listen in - the web address is https://www.eliteliveradio.com. We are currently broadcasting a trial service for the next couple of weeks. Do listen in - and let me know what you think.