How to use sym num layer on my custom layer ??

[ISouthRain]

Hello, first of all, thank you for your work, miryoku is great.

I use Miryoku for ZMK
I have customized the new layout and I named it: APPAD
This is my layout:

#define MIRYOKU_ALTERNATIVES_APPAD \
&kp Q,                 &kp COMMA,          &kp DOT,               &kp SLASH,                  &kp T,            U_RDO,             U_PST,             U_CPY,             U_CUT,             U_UND,             \
U_MT(LGUI, A),         U_MT(LALT, LEFT),   U_MT(LCTRL, UP),       U_MT(LSHFT, DOWN),          &kp RIGHT,        &kp LEFT,          &kp DOWN,          &kp UP,            &kp RIGHT,         &u_caps_word,      \
&kp Z,                 &kp X,              &kp C,                 &kp V,                      &kp B,            &kp HOME,          &kp PG_DN,         &kp PG_UP,         &kp END,           &kp INS,           \
U_NP,                  U_NP,               &kp ESC,               U_LT(U_NUM, SPACE),         U_LT(U_SYM, TAB), &kp RET,           &kp BSPC,          U_LT(U_FUN, DEL),  U_NP,              U_NP

I switched APPAD: &u_to_U_APPAD in the Fun layout, and I also tried: &mo/&to/&tog U_APPAD

ZMK layer link: https://zmk.dev/docs/keymaps/behaviors#layer-navigation-behaviors

However, the end result is:
Although I have switched to the APPAD layout and confirmed that other keys of this layout are valid, the layout switching of U_LT(U_NUM, SPACE) in the layout does not work, and similar &lt to U_NUM U_SYM layout cannot be performed.

I want to use my custom layout APPAD like BASE layout to use U_NUM U_SYM.
How can I solve this problem?
I use Miryoku for ZMK

[manna-harbour]

See the Tip box in this section: https://zmk.dev/docs/keymaps#layers.

Also, if you don't need the Extra layer (https://github.com/manna-harbour/miryoku/tree/master/docs/reference#additional-features) you can just substitute a custom Extra layer instead using #85, which already has an appropriate position in the layer order.

[ISouthRain]

Oh, very good.
I solved the problem. The reason is that ZMK layer has a level feature. Only high-level can switch to low-level layer

Thanks you.

[manna-harbour]

If you wish to use multiple base layers (with a toggle), e.g. one for QWERTY and another for Colemak layouts, you will want these layers to have the lowest value possible. In other words, one should be layer 0, and the other should be layer 1. This allows other momentary layers activated on top of them to work with both.

So, for Miryoku, extra base layers should be next to Extra.