Thought I'd copy and paste this from the FB Dog Training and Advice group in case it is useful.
𝐍𝐞𝐰 𝐩𝐮𝐩𝐩𝐲? 𝐒𝐨𝐜𝐢𝐚𝐥𝐢𝐬𝐢𝐧𝐠 𝐝𝐮𝐫𝐢𝐧𝐠 𝐭𝐡𝐞 𝐂𝐎𝐕𝐈𝐃-𝟏𝟗 𝐜𝐫𝐢𝐬𝐢𝐬
If you have a new puppy there is no need to worry unduly about how you are going to socialise him/her in the current situation.
Socialising is not just about playing with other dogs or meeting lots of people. Being sociable is about being able to walk politely past people and dogs. Now with social distancing we have the perfect opportunity to take puppy out without having to worry about puppy being frightened by a boisterous “he only wants to play” dog or overwhelmed by the attention he attracts from strangers and exuberant children or conversely of teaching him that every dog he sees is a playmate and every person a new best friend.
Whether your puppy is a shy introvert or a confident extrovert you can take puppy out in your arms, a sling, in the car and find somewhere to sit and watch the world go by and eat treats and play with you.
Puppy can get used to traffic, seeing people, dogs, farm animals if you live in the country all from a safe distance and this can continue as he gets older and is walking on harness and lead or can go off lead or on a line for a run about. Try and visit as many different locations as you can during the first few weeks!