In this work, we investigate the decays of the fully open-flavor tetraquark state $X_0\left(2900\right)$ which was observed by the LHCb collaboration very recently. By using an effective Lagrangian approach, the partial widths of $X_0\left(2900\right)$ are estimated, where $X_0\left(2900\right)$ is assumed to be an $S$-wave ${\overline{D}}^{*}{K}^{*}$ hadronic molecule with $I=0$. It is found that the estimated results are in agreement with the experimental observations. Moreover, we also predict the decay behaviors of the other unobserved ${\tilde{X}}_{J(J=1,2)}$, which are the spin partners of the $X_0\left(2900\right)$ in the $S$-wave ${\overline{D}}^{*}{K}^{*}$ picture. It is pointed out that the ${\tilde{X}}_1$ state with $I=0$ is a broad state with the width more than 100 MeV, while another ${\tilde{X}}_2$ state with $I=0$ is a narrow state with the width approaching half of that for the $X_0\left(2900\right)$. In addition, our results also show that the ${\overline{D}}^{*}K$ mode is expected to be the dominant decay mode for both ${\tilde{X}}_1$ and ${\tilde{X}}_2$. Searching for those unobserved ${\tilde{X}}_{J(J=1,2)}$ in the future experiments might be helpful to understand the nature of $X_0\left(2900\right)$.