There are only two step for this whole code.
The first one is the hardest to find, but try out all ciphers that you know!

As said in the hint, the first step is the hardest.
The Bifid cipher has been used recently a few times, so it is wise to add it to your list of “first things to try”
sixwrytwohollandxnineeeighth
Replace the numbers for the final solve
6wry2hollandx9e8h

Look for meaningful words when using the different types of transpositions (Skip, Rectangle, Railfence).

Arrange the code in a grid of 5×4

Now reverse just the even rows (2 and 4)

Read each column from top to bottom, starting with the most left one.
9yhb5nikolaitalm6w7g

Throwing nikolaital into Google gives us the Wikipage “Matter Valley“, also known as “Nikolaital“.
We know matter is a known keyword, so pop that into our code for the solution.
9yhb5matterm6w7g

I can feel you thinking “How on earth did you figure out to only reverse those rows?!?!“.
Don’t worry, at the start I felt the same way. But with time and the right tools you will learn to notice such things, learn to real columns and rows in different ways.
Practice makes perfect!

Count them and think why would there be only so many of them.
What do you know that has such a constraint to it’s different values?

Looking at the ranges of the letters and numbers, we notice that if we were to substitute the letters with numbers (starting at a=0..j=9) and numbers with letters (00=a..05=f), we get a very good mixture of hex values!
djg03h00g05gjgjhag02gbhdg03gbhggjgjhidfhd
becomes
396d7a6f6969706c61736d61766969783573

Now we have a code length that can be paired up
39 6d 7a 6f 69 69 70 6c 61 73 6d 61 76 69 69 78 35 73

Convert from hex to text
9mzoiiplasmaviix5s

and replace the Roman numerals with numbers for the final solution (be careful with, that v is part of the format, not the Roman numeral 😉 )
9mzo2plasmav2x5s

Sometimes codes seem much more difficult than what they actually are.
Always remember to analyse the text, see what you have and what you don’t have and what the ranges are for what you have.