For fisheye, the focus distance is like from very close to infinity. So dun worry about getting out of focus shots from it, you can't manual focus anyway.
for holga, its range focusing, there's 4 distance icons to chose from, a half body human icon for about 1-3m range, a small group of people icon for 3-5m range, large group of people for 5-10m & a mountain for more tha 10m to infinity. So if you set the correct range, you should get the right focus. Exposure is basically how much you know about the film you used. ISO 100/200 for daylight, daytime shoot. ISO400/800/1600/3200 is for lowlight/night time. if you use ISO 800 to shoot daytime shoot, most likely you get overexposed shots.