Should I assign certain google ads per keyword or more?

Use 3 keywords for each campaign with relevant keywords to each other to maintain high-quality result also the ad group and titles. So in your case, I think you should create 3 different campaigns and add as the following scale.

1st campaign = 3 keywords
2nd campaign = 3 keywords
3rd campaign = 4 keywords

In the campaigns, you can choose certain ads to be shown for certain keywords.

Should linked Adword with analytics or not?

Based on the benefits that bring up when linked analytics account with Adword for your campaign, I believe that you will not make the wrong decision. Here is the proof, ( by google ads academy)

google ads linked analytics benefits explaination

As the screenshot is shown above, I think you will not miss it. or your campaign will not optimize for the best result.

Test for conversion measure in google adword

Hello, I use my website as a way to measure the conversion of events, but when doing some tests I found out the source and the media because I saw that they are different. I’ve done a test conversion in a direct way and it’s showing me in GA that it was CPC or says it came from a video on youtube. What could that be?

Facebook Ads vs Google Adword, when to use?

In Marketing Online, Some people use facebook ads as their main ad promoting, other use adword. Then, what are the differences between them? 
By original, it is divided into 2 these points:
1, Facebook Ads is belong to Facebook, Largest Social Community
2, Google Adword is belongs to Google, a biggest search engine
By purpose, two points for it
1, Facebook Ads for selling items, getting fans, building community page, draw traffic to your products. I mean, if your services or products mainly for online selling. then facebook is your choice.
2. Google Ads, for large company, and large services like outsourcing, it services, competitive in google search results. If you want to draw traffic from google, you need to use google ads.
And so on, if you have more idea, please share with me, thanks.