How do I assign a numeric value to a non-numeric value and then connecting it to another table?

Let me try to explain again: 

Main table: 

Category: 

1

3

5

7

22

18

Table A: 

Item-no:                Name: 

1                            Apple

3                            Orange

5                            Strawberry

7                            Lemon

22                          Mango

18                          Banana

I would like to merge these tables, so the values in "category" in the main table gets replaced with "name" from Table A. The values are the same in "category" (1, 3, 5 etc.) and in table A under "item-number"(1,3, 5 etc). I would like to see the name for that item-no. in the main table instead of numbers. 

I am still a newbie in Power BI, so please give me a dummie explanation 🙂

Best regards, 

Lisa