Fixed income level 1 full price


I don’t understand how price is calculated
I need detailed explanation for the solution

Step 1: you value an 18 year bond running from 3 April 2031 to 3 April 2049
Present Value =4.625\times\sum_{n=1}^{18}1.035^{-n}+100\times1.035^{-18}=114.838
The cash flows are 4.625 at the end of each year and 100 at the end of year 18. The cash flows are discounted back to the present day at 3.50\% p.a.
They expect you to do it on the calculator and tell you the inputs