Use a slow cooker at least once a fortnight, mostly for casseroles of sausage/bean diced pork, chicken legs/breast/thigh and stewing steak.
Have made yogurt and stock in it, but much prefer doing that on the stove.
Had the same one a Boots Swan slow cooker with a ceramic removable pot for about thirty years.
It still looks brand new, being a doddle to keep clean.
There are plenty of good books, ebooks and recipes online for slow cookers.
I never pre fry if doing a slow casserole type dish.
Put the slow cooker on for about 15 mins on High before adding the ingredients, then put on auto and leave it to do its stuff for about 5-8 hours.
Do give it a stir up before its last hour of cooking, but do it quick as you do not want the lid off too long.
If you want dumplings and I always make them for pork and stewing steak casseroles, you can make the dumplings as normal. Put them in the pot for the last hour rather than the 15 mins you would normally do with an oven casserole. Another method that works well is to put the pot uncovered pot under your grill for about 15 mins to cook the dumplings.
Always find my homemade stock makes a good thick sauce, just make the stock up to the level of your meat/veg I find produces the best results.
For stewing steak I make up a thick gravy with your favourite granules, say half a cup and add that along with the stock to the meat/veg level and its a lovely thick sauce.
I also add a few spoonful's of Waitrose cooking wine in casseroles as that can be poured straight in as its been dealcoholized and no pre cooking, which is required for normal wine you would add.
You could always add a bit of cornflour to just your sauce at the ned of cooking and mix it on a hob to thicken up a bit if you prefer.