4 Data fields in one screen??

Sure it's possible, that's the first thing I set up.

You've read the manual, yes?

Go to Menu > Activity Settings > Data Screens> Screen1 > Layout, tap Enter and it displays the sample screen, scroll up/down to select whether to display 1, 2, 3, or 4 data fields, Enter again to save.
Repeat for Screen2 if desired, then repeat again for whatever other Activity you wish to set up.

Thanks for your quick response gpb11.
Unfortunately I can only choose for a maximum of 3 data fields. Maybe I should check for a software update. Currently I'm running version 3.2

Thanks for your quick response gpb11.
Unfortunately I can only choose for a maximum of 3 data fields. Maybe I should check for a software update. Currently I'm running version 3.2

I'm on 3.2 and have 4 fields. I think I had 4 fields on the previous version also.

I've had 4 fields from the get go as well.

Unfortunately I can only choose for a maximum of 3 data fields. Maybe I should check for a software update. Currently I'm running version 3.2

I'm on 3.2 and have four data fields showing on both data screens.

So feel free to check for software updates all day long, but that's as likely to solve your problem as banging two sticks together.

Follow these steps and tell us what happens:
From the watch face, tap Enter; you should see an activity displayed such as Run.
While the activity type is displayed, tap Down to get the menus.
If Activity Settings is not displayed, tap Up or Down until it is displayed, then tap Enter
Data Screens should be displayed. If not, tap Up or Down until it is, then tap Enter
"Screen 1" should be displayed. If not, tap Up or Down until it is, then tap Enter
"Layout" should be displayed, with a subheading of "3 Fields". Tap Enter
The watch now displays the three fields.
Tap Down.
The watch now should display four fields.
Tap Enter
You should see "Layout" displayed, with a subheading of "4 Fields".
Now use Down to select the data fields and select which data elements are displayed in each field.

If all else fails read the manual ...

But yup Activity Settings, Data Screens, select Screen 1 or Screen 2, Layout is where you change the number....

If all else fails read the manual ...

While I am often among the first to suggest people Read The Friendly Manual, I have to give the OP a pass here because quite simply the Garmin manual is woefully lacking in details.

Here is the entirety of the section talking about customizing activity screens:

Customizing the Data Screens
You can customize data screens based on your training goals or optional accessories. For example, you can customize one of the data screens to display your lap pace or heart rate zone.
1 Select Menu > Activity Settings > Data Screens.
2 Select a screen.
Some screens can only be turned on or off.
3 If necessary, edit the number of data fields.
4 Select a data field to change it.

There's a bit of finesse to step 3 that the manual writer never gives any further detail on. While techies such as you and I just dive in and figure it out, many people are not "wired" to so easily do so.

Link to manual: http://static.garmin.com/pumac/Forerunner_230_OM_EN.pdf

True that could be clearer although if you follow those instructions, the number of fields hits you straight away.

Anyway how is the OP getting on?

I know this is ancient history, but I'm a retired computer programmer and I would never have written "If necessary, edit the number of data fields" -- I would have told the user how to do that. (I stumbled on the trick by luck.)