Let's see if we can figute it out:
Aim the meter at the subject to be photographed.
The meter needle will move and settle.
Turn the dial so the f/stop you want to use or the shutter speed you want alignes with the needle.
Read the shutter speed or, f/stop that alignes with the ASA (ISO) rating of the film you want to use.
That is it. Nice and simple. The meter works the same as say a Weston III or II or most other selenium meters such as the Pilot/Pilot II or GE PR-2. All are similar in how to use.
The drawback of the selenium meter is the cell responds better and faster as the light lumens increase. Not a meter for low level use. I used Weston seleniums for quite a few years and if the meter reads right they can be as good as anything out there. I only switched after picking up some CDS cell meters at a bargain price. For better, you can pick up early analog meters using the 625 cell that is no longer available and use an adaptor to use a newer battery. I use a pair that back when made were very well respected by professionals; a Weston Ranger and Metrastar (made by the company that made the external meters for Leica). Each was bought for less than $25 and physically in like new condition and measured within a .25 stop of my Bronica metered prism and each other.
If you want to keep and use the meter and it is off, try Quality Light Meteric in Hollywood, CA for repairs. He can cut a new cell. He is the go to guy for Westons and does others as well. He maintains the meters for the Hollywood studios so ain't no beginner. I'd have disposed of my Westons but, held onto them thinking of sending them to him to refurb.