Accidental entry to Lomography-FED5B Russian

Planned for another walking trip along another old street in Singapore - Keong Saik Road. This street has many preserved old shop houses and currently many use it for restaurants/hotels and businesses. There are still some old tenants staying put. One of the shops we explored was an old antique shop. I saw a old rangefinder and bought it after the shop owner persuaded me. My mind was thinking to get it as a display set as I thought it may not be working any more. . Checked the shutter and the exterior, still looks good. Test further on the aperture opening and different shutter speed, seems to be working 100% good. Only a speck on fungus was found in the lens.
Bought 3 rolls of negatives from a Lomography shop near Chinatown, I started to load it. It was 10 years ago since I last touch a film camera (SLR with motor winder)and the first time I load a manual camera since 20years with my Dad's OM-1. Ok, everything went smoothly.

The issue come now as my modern OM-D Olympus , there is a exposure meter built in but this 1977 Russia rangerfinder (fixed lens 55mmf2.8) does not. So I got a bit lost..ha ha. Now I realised how modern DSLR or camera has made us so easy to know the exposure setting. Nevertheless, I just shoot with a iso100 film, set the aperture at f2.8 and play with shutter speed 1/60s to 1/125s in the day light. I still remember that negative film has a higher tolerance of exposure compared to slide colour film and digital.
I came home and search the web to see how to use this old russian camera. Seems to have alot of info. Will develop my 1st roll and see how it goes. FIlm has it's fun and no rules mindset .I still think digital is the way to go for it's convenience and instant result. Film Lomgraphy has a increasing fan base worldwide and I can understand why.