Right now, I'm preparing the stuffs I need for tomorrow's hike.

MI am charging my power bank and AairPpods are charging.

I've also prepared some clothes in case I sweat my clothes get soaked with sweat after hiking.

I justRecently, I bought a new insulated water bottle to carry some hot water with me because the weather has been getting colder and coldereveryday.

And now I'm arranging the pictures and videos on my phone to make sure that I'll have enough space forto capture tomorrow's views.

I've baked a multi-grain bread and washed three pieces of fruits: an apple and two oranges.

When I read “I baked a multigrain bread,” I imagine you mixed flour, yeast, salt, etc. to make bread dough and then baked it in an oven, presumably producing a loaf or loaves of bread. Is this what you mean? I’m asking because “我烤了一个杂粮面包” could also mean you toasted or heated up a piece of multigrain bread (which had already been baked before you purchased it).

(Note that “a bread” means an unspecified amount of a kind of bread. It does not mean “a piece of bread.”)

The countable form of “fruit” means “kinds of fruit.” You washed two fruits (two kinds of fruit), but three pieces of fruit.

I've also prepared some extra clothes in case I sweat my clothes afterre sweaty after I finish hiking.

“I sweat in my clothes after hiking” means you don’t start sweating in your clothes until after you’ve finished hiking. It seems more likely that you would sweat in them while hiking and they would still be sweaty after you finish hiking.

Right now, I'm preparing (some) stuff for tomorrow's hike.

I've also prepared some clothes in case I sweat in my clothes after hiking.