Hope for advice and critique (i'm sorry for my poor English)

Hi,i'm a middle school student and i'm learning drawing.i'm so sorry my english is not good,i'm foreigner.

These pictures are my practice for the past few days.I really want to improve myself,but i'm have some problems,i hope to get some advice about the accuracy of human proportions,and how to improve painting speed.

During practice ,i found that i could not focus my eyes on drawing the motive force,i'm always trying to draw details,which is out of proportion and slows me down.And I don't know much about muscles, either.

I want to know:

1.Should I go to an anatomy book first to learn muscles? Or should i focus on line practice first?

I have some book about anatomy,but when I read them I realized that I still had no idea what muscle was going on.When I practice, Iam always confused about the outline of the person in the picture.

2.Should I start with a simple figure pose?

I have always liked drawing and have some self-taught basis.When I sketch,I always tend to summarize details,resulting in poor completion.I think I should draw the muscle movements in each sketch in more detail.So instead of a veay complicated pose, maybe I should start with a easy pose?

3.How to quickly decide the basic proportions of the human boby?

I found i have a bad habit of drawing, I always draw directly from the physical appearance, rather than identifying the skeleton first.This makes the poses of my paintings change all the time.

These are the problems I have encountered during this period and my own thoughts,I hope to get comments and suggestions.I will reply to all comments,I hope you don't mind my poor English:) (i will study English hard.)

Good evening, Lunchuan, and welcome back. Well, to comment your your more than recent pieces, I must do say, that your figural constructions and forces are all totally on the righter track, in terms of the bone and muscle anatomy, but in terms of the relationships, but in terms of edges and silhouettes, but yet, the gestalt, but the line efficiency and exaggeration but with boiling things down to the raw-er essence could use more work, so how would you love to try gesture drawing to warm yourself up the every bone and muscle in the human body?

But, these simpler poses could use a bit more dynamics in the poses, so why don't you please loosen them up as a warmup, but, you don't really need to worry about the more complex relationships so soon, so how would you like to be more softer in your lines to them along with the spaces and forces?

As a result of three things:

1) To make your bones and muscles more distilled than they actually are.

2) To make the more simpler poses more edgier but vital in any position and angle.

3) To be even more intuitive in terms of your body and head relationships.

And, if you're completely curious about body caricatures, kindly look into the Mike Mattessi forces Livestreams on YouTube, like this one: