A good choice! Some advise:
1> Download and install Mystuff with it's supporting TAPs and recommended firmware to both before starting. Your going to need to learn a new remote so you might as well learn it with Mystuff installed.
2> After you've done a channel scan, delete the channels you wont watch (topup tv, encrypted, kids and adult always go from mine). The TF5810 is a little low on memory and deleting these unwatched channels make the EPG (program guide) much smaller. I'm not sure if this is done in the same way on the TF5810 as my TF5800 so i wont say how it is done.
3> Have a read through
Toppy.org.uk ~ Index. There is loads of information on there.
4> Download the Mystuff manual and have a read
MyStuff 6.1 start off with using the EPG, setting timers and watching recordings (archive). Mystuff is complicated, perhaps i should say it has lots of features, it's quite easy to use. Once you have the basics you soon pick up other things.
5> The latest Mystuff has series link. Don't use series link on Five's channels. They don't broadcast accurate series link information which will make you miss programs. Use "text searches" instead.
Good luck and enjoy. I've had mine for about 4 years now and wouldn't be without it.