Family history research tips and resources

Hi hope I’m okay to ask this here. I’m a Scottish person of Limburgish heritage from my maternal grandmother (she’s from Schinveld and got extended family all over Parkstad) and was hoping to try and learn more about her parents and siblings since I’m planning to do a trip to Limburg in a couple of months. In particular I’m quite interested in learning more about her father and what exactly happened during the war (apparently got taken by Nazis for a couple of years when my oma was a baby but not much detail was given). Any advice on places/websites I can go to for information?