Ahh he's lovely and he does have a touch of the Donald about him. But I'm going to overlook this and imagine you called him Reese after Reese Inside No9 / League of Gents Shearsmith.
I am happier in my head now 
Sticky Hay Thing - we got some PetBags from Amazon, . Shake as much off as you can, seal up the fleece with a capful of a non scented detergent (I bought Ecover) and all the mess stays in the bag. Hang out to dry , shake the bah, job done . No string smells , no Zoflora , they are respitatory sensitive . No fabric conditioner , it stops the fleece wicking.
Put newspaper under to absorb
His diet needs to be varied , not too much dark green as it can lead to high calcium deposits and bladder stones especially in boars .
If he turns his snout up , maybe let him try a tiny bit of new foods over several days . They go for the favourites first . Ours would be parsley , then spinach. If they had kale it was left till their bums were in danger of slamming shut and lambs lettuce for the day Hell froze over .
Carrots with leaves were devoured . Carrot peelings were stamped and peed on.
The best clippers I found were like scissors with a circular notch , so rather than sliding over the blades (like scissors) they were like clippers as the blade in the circle bit met .
You need to trim the dull opaque bit , the cutters will cut neatly without crushing or twisting .
The front paws claws tend to curl in which is trickier .
Guinea-pigs don;t like having this done and will protest , grab their paws back and throw their heads back.
Towel wrap , get someone to hold the body , stay calm and ignore the protesting little rodent . It's sometimes easier to do front legs/back legs on a different day .
If he has any pink feet and claws its much easier to see the 'live' bit . If his nails are very long , trim a bit regularly to shrink the quick back.
If you do catch a quick use cornflour in an eggcup as a styptic. They do bleed but it stops .
He'll need a bath if he gets niffy but meantime you can trim the fur round his rear to keep it tidier . Hold a bit of fur between forefinger /middle finger , keep your fingers next to his skin .
Were his previous cagemates male? He might not like other boars but if you got him castrated he might like a Wife? Something to consider , they do thrive in company .
I didn't have insurance , I looked online , there was a company that insured Exitics but it's ££ . Guineas don't need vaccines . I used Xeno 450 drops ( mites, worming)
Do find a Vet who specialises in piggies , many vets will have a Small Animal Vet ( I used to take mine to a guinea-pig specialist but it was an hours drive each way !)
Enjoy him, piggies are lovely , shy, greedy and noisy little creatures . They eat all the time so plenty of hay to keep them busy , wears the teeth and keep the digestion going.
They pooh a lot .
Mine rarely drank water even in Summer but peed plenty . The water bottle was only used at 3am , to wake me up