If you follow TOMM, or any other method, can you advise me..

[TheLeigh]

where/how to start please?

Downstairs rooms are a bit untidy and in need of a good clean as I seriously have fallen behind over Christmas.

Upstairs two rooms need decluttering, one is a total mess (my office/junk room) the other bedroom needs less decluttering but is untidy and lacks decent storage.

Not sure how to get started.
I have been thinking to spend the next couple of weeks doing Level 1 jobs each day and just focusing on the rooms that need decluttering.
Or should I follow the plan so ie Monday level 1 and living room, Tuesday would be level 1 and declutter, but not likely I'd get much cleaning done if I'm spending time on the declutter.

I'm feeling overwhelmed. No idea how to get started!

The boot camp! Tough week but you'll have a fresh slate then to start the levels.

Oh this is topical for me too, I've been trying to find a video for the boot camp week on YouTube without success. I've binge watched a lot few of her other videos and felt quite inspired but I think I need a good deep clean first.

I would do level 1 and level 2 and then do 60 mins of decluttering every weekend.

I would do boot camp first to set you up for weekly half hour.
If the house isn't decluttered enough the half hour doesn't always get things sorted.