Hi and welcome.
Please give us some additional info.
You can creat a signature by going to User Control Panel (top left under the TFP logo), then Profile, then Edit Signature. Tell us your pool specs and equipment info.
Is this a manual vacume, the kind with a vac head, and a hose that attaches to your skimmer, possibly with a vacume plate?
Did you "prime" the hose first? You do this by placing the vac hose on the vac head, and putting the vac head in the pool. Take the other end of the hose and hold it up to the return. The water will force out any air trapped in the hose, and the vac head will rise up and you'll see lots of bubbles. When the vac head sinks again, it's primed. Keep the end of the hose under the water and attach it to your skimmer. This should keep the hose primed and prevent you from losing suction.