My minimum standard for well-written English is basic grammar correctness, without going into the niceties of compositional unity and clarity, rhetorical flair, and general readability. From that standpoint, I'm afraid that the memo that you presented doesn't meet that minimum standard.
The basic clean edit that I've performed below should give an idea of the basic grammar inadequacies of the original (It wasn't practicable for me to show the actual editing marks and corrections, so you just have to figure them out yourself.)
Here's the edited version:
“And for one of my most important concerns, I’ve observed that these past few days, few among you are using instructional materials at all but only chalk and board. Although the subject is ESP [Edukasyon sa Pagpapakatao], you should already be using your IM’s [instructional materials] so that next year you can just pick them up and reuse them. I also heard that some of you are saying that you are being oversupplied with manila paper. I want to remind you though that your supply of manila paper is meant not only for your IMs; they are also meant to be used by your pupils as material during their activity. It’s good that today in particular, I was able to see teachers who are really teaching with IMs. You see, I came up with these these observations not only when I sat on your table and watched you teach but also when I roamed around and was able to see you and hear how you actually teach.”
That's all.