International Student Apart Guarantor Company

Hi! Ok, so I was looking at chintai dot net and the have a filtering system that allows me to narrow down my search to apartments that accept international students, so I've been looking at those but I've come across some terms that I'm not so sure I understand, thought someone here could help:
「家賃保証会社利用可」google translate tells me this means "guarantor company available" and later it says 「保証会社任意加入（実費）」"optional subscription (actual expenses)" -- what does this all mean exactly? The real estate agency that handles that apartment has a guarantor company I can use? or should I get a guarantor company on my own?

Also, if it says 「家賃保証会社利用必須」"guarantor company required" am I supposed to subscribe to their own guarantor company and I'm all set? Should I also have a guarantor of my own? I'm so lost :/

I'm very confused please, if anyone has gone through this, tell me your experience please! Would they allow me to rent these apartments without a good level of Japanese? I'm willing to get someone to help me with the contract, but for visiting the apartments and everything before that I wanna do it on my own, cause my Japanese friend is not a SUPER close friend of mine so I didn't want to bother them.

Background info about me:
1) I'm going to Tokyo for 1.5 years to study at a language school, I know a little a bit of conversational Japanese and very little knowledge of kanji (about 300-400), very basic stuff.
2) I'm of Japanese descent (sansei) so my second name and one of my last names can be written in kanji...I read that that helps?? idk just throwing this in here just in case...
3) I booked a room in a sharehouse for my first month in the hopes that on those 30 days I can find an apartment, is this feasible?

ask your school... they can help you to sign house.