Flush your flask out with nitrogen by evacuation followed by re-pressurisation with N2. Add the catalyst (careful, most are pyrophoric) and the substance in a suitable solvent, ethanol, ethyl acetate etc. (avoid methanol as it can decompose to formaldehyde and CO causing problems). Evacuate, being careful not to loose the solvent and repressurise this time with hydrogen. Repeat three times. Seal the system and stir rapidly until the reaction is complete. You can also use a burette to measure the hydrogen uptake if you wish. If you need to heat the reaction you will need a pressure vessel made from stainless steel or the like.These can be fitted with valves to measure H2 uptake. When done remove the catalyst by filtration, don't let it dry out (fire hazard) wash the solid two or three times with the reaction solvent and before you do anything else place the catalyst into a beaker full of water. You can collect these water suspensions, most catalyst providers will take them back for metal re-cycling.